[Translation: The second reason, which is often the cause of problems, is the signalling system. And the third reason is the door, which malfunctions. Our request to the maintenance service provider is to concentrate on these three issues.]

Busan Rails -- whose three-year maintenance contract with the DOTr for the MRT-3 expires in January 2019 -- said in July that the system's problems are caused by the poor condition of the rails and design flaws.

[Translation: This is not supposed to be normal because the causes are clear to us and clear to them. The only reason we're ending up in this situation is because we've proven that since we took office a year ago, the right parts haven't been purchased yet.]

[Translation: If ever Busan's contract is terminated, we could conduct bidding in the next three months. In the meantime, the government is ready to take over the MRT-3's maintenance, similar to what we have been doing with the LRT.]

No more lines?

In May, the DOTr said that long lines at the MRT-3 would disappear by December 2017.

The MRT-3 runs only 20 three-coach trains at most during peak hours due to power constraints. This is despite the arrival this year of 48 additional coaches from a 2014 deal between Chinese company Dalian Locomotive Corp. and the Aquino administration.

Officer-in-charge for Operations Deo Leo Manalo said in a Senate hearing that once the MRT-3's power supply is augmented, the DOTr will increase MRT capacity by additing another coach to its trains on top of the five new trains.

However, Chavez told lawmakers on Wednesday that the coaches may be returned to China if a third-party evaluator finds these unsuitable for Metro Manila.

The 25-kilometer subway will run from Mindanao Avenue in Quezon City to the FTI complex in Taguig City, with an additional line extending towards the Ninoy Aquino International Airport terminals in Pasay City.

The subway is expected to cut the trip from Quezon City to Taguig to half an hour. The project, which is slated to be completed in 2022, can take 350,000 commuters daily.